三峡库区消落带完整淹水后土壤重金属分布特征及其影响因素

通过野外采样和室内分析，对三峡库区小江流域消落带土壤重金属Cu、Zn、Cr、Ni的含量特征进行了评价，并同时对其在消落带上的影响因素和分布特征进行了研究。结果表明:Cu、Zn、Cr、Ni在消落带上的含量分别为28.69，126.03，57.20，27.91mg/kg。相关分析表明，Ni、Cr、Cu的含量明显受土壤理化性质影响。其中，有机质、粗黏粒和黏粒均与Ni、Cr、Cu含量呈显著或极显著正相关，粉粒与Cr、Cu呈显著正相关，砂粒与Ni、Cr、Cu均呈显著负相关。逐步回归分析表明，Cr、Ni主要受粗黏粒含量的影响；Cu主要受砂粒含量的影响。单因素方差分析表明，Cu、Zn、Cr、Ni在消落带不同区段的分布存在显著性差异，总体呈从上游到中下游逐渐增大，下游又有所下降的趋势，其在消落带不同高程上分布的差异性不显著。

The Distribution Characteristic of Soil Heavy Metals and Their Influencing Factors in Water-level-fluctuating Zones of the Three-Gorges Reservoir Area

The concentrations of soil heavy metals in water-level-fluctuating zone are directly associated with water safety and human health. In this study, the concentrations of Cu, Cr, Ni and Zn in water-level-fluctuating zone soils of the Three Gorges Reservoir (TGR) area were determined, and their influencing factors and characteristics of distribution were studied. The results showed that the total concentrations of Cu, Zn, Cr and Ni in the water-level-fluctuating zone soil of Xiaojiang river in the TGR area were 28.69 mg/kg, 126.03 mg/kg, 57.20 mg/kg and 27.91 mg/kg. Correlation analysis showed that Ni, Cr, Cu were significantly affected by soil properties. There were significantly positive or positive relations between organic matter, coarse cosmid, cosmid and total Ni, total Cr, total Cu. There were positive relations between silt and total Cr, total Cu. There were negative relations between sand and total Ni, total Cr, and total Cu. Stepwise regression analysis showed that Cr, Ni are mainly affected by coarse cosmid content. Cu is mainly affected by sand content. ANOVA showed that there were significant differences of total concentrations of soil heavy metals in each section of the water-level-fluctuating zone, where the concentrations of soil heavy metals increased gradually from the upper stream to the middle and decreased in the downstream. There was no significant difference in their distributions at different altitudes.